The Navy body fat calculator: This calculator to measure body fat is based on a formula developed by the US Navy. It takes weight and waist, hips, forearm, wrist and gender to give you a percentage body fat measurement so have a tape measure to hand.

Calculators with Calipers: If you do have a body fat caliper there are a few calculators here where you enter your measurements in millimetres with your fat caliper and the fat calculators will give you your body fat percentage.

Have you got your own body fat calculator, Doc?

Funny you should say that Moose, I’m working on one right now…

Coming soon …. to the top of this page … Halls body fat percentage calculator.

Why is Body Fat Percentage Important?

The reason that the percentage of body fat you have is important is that it is a good indication of your overall body composition. Whilst body mass index bmi has been the standard measure of how healthy your weight is, this height to weight ratio does have limitations and body composition is one of them. For example, if you are a relatively slim woman with a BMI of around 19.5 with a fat tummy, you may be MORE at risk health wise than an overweight lady with a BMI of 27. Why? Because the distribution of fat is an important indicator of health and the slim lady may have a higher percentage of fat than than the larger lady, who may be very muscular and big-boned.

Dear body fat you have two choices – make your way to my boobs or ship out.

What is body fat percentage?

Body fat percentage (BFP) is simply the amount of fat, or the fat mass, of your body divided by your overall total body weight (or mass). This does not necessarily mean that once the percentage of body fat has been deducted from the equation, that everything else that is left is muscle mass. After the fat percentage of the body has been calculated everything left over is known as ‘lean body mass’ or lean mass. Lean mass includes water, bones, organs, hair and muscle which is a little misleading as bones and hair are not that ‘lean’.

I have got a six pack, it is very precious. That is why I protect it under a layer of fat.

Same for me. Six pack … coming soon.

Is all Body Fat the Same?

All body fat is not the same. There are two types of body fat and these are:-

Essential Fat: This type of fat is found in most parts of the body such as nerve sheaths, walls of organs, bone marrow and muscles and is essential to normal functioning. Women have a higherpercentage of essential fat as it is also found in the breasts, lining of the uterus, hips and thighs. According to the American Council on Exercise (ACE) the percentage of essential fat should be around 8 – 12 % for women and 3 – 5 % for men (but these figures do vary according to the source).

Storage Fat: Now, this is mainly the fat that we are talking about. This is the type of fat that we do NOT want too much of in the body. This fat forms the subcutaneous fat (or the fat under the skin) that you can physically pinch and also visceral fat (or abdominal fat) that is deep in the abdomen surrounding the organs for protection. It is the ‘storage fat’ that is used in metabolism and energy expenditure, and as we all know, too much of this can have some serious health implications.

Body Mass Index (BMI) or Body fat Percentage?

The body-fat percentage may be a useful tool for predicting an individual’s health. In comparison to BMI measurements, whose normal ranges are based on a very large number of people, the percent body fat indicates body composition (and therefore health risks) of each individual. However, percent body fat does vary according to other factors such as race, gender and age. One study that examined 665 people on the relation between BMI and percent body fat found that age, gender and race play a role in what is a healthy body fat percent. If we are to have healthy ranges or an ideal body fat percentage range then these factors need to be taken into consideration. BMI measurements and body fat percentage measurements both have a role to play in developing healthy ranges for assessment of future health risks or obesity-related diseases.

Now that is a big tummy!

Yes, waist circumference measurements can also be a good indicator of health risks. Find out more HERE.

The Body Fat Percentage Mathematical Formula

The formula below for calculating body fat percentage was taken from research carried out in 1991 by Deurenberg which compared body mass index bmi and body composition. The relationship between body fat percentage and BMI was analysed taking the age and sex of participants into account and the formula below devised. The research showed that the estimates of body fat percentage according to BMI measurements and the formula were valid, but did tend to overestimate the body fat percentage.

There are different formulas by other scientists too for working out body fat percentage, like this one by Jackson, that takes into account race as well as age and gender.

That looks a bit complicated. I really, really hate maths.

Yeah, math is the only place where people buy a hundred watermelons and nobody wonders why.

… and why is it called a calculator and not a calcunow?

Dr Halls problem with the Body Fat Percentage Mathematical Formula

The problem with the mathematical formula for body fat percentage is that when Body Mass Index (BMI) and Body Fat percentage are charted on a graph the resulting straight line is linear. Below you can see an example of different mathematical formulaes to predict percentage body fat from BMI, age and sex. The pink line is an example of the mathematical formula shown on this page above. You can see that all the graphs are linear lines.

However, body fat percentage has a curved distribution relative to body mass index, not linear, as shown below.

If you were a slim woman with a BMI under 20, the pink line formula would say you had 25 to 30% body fat, which is totally wrong.

I’d guess about 15 percent, from the curvy chart above.

That formula is even on wikipedia. The world needs something better and I shall be looking at my own Body Fat Percentage formula soon.

So the body fat percentage formulas are not as good as they could be.

Let’s rephrase the question. If you know your BMI, do you also know your body fat percentage? The answer is YES, but only if you are kind of average in all respects (well, not mentally). The above formula works well, if you are average height, average weight, and aged around 30.

Some studies are suggesting that body fat percentage may be a better predictor of some diseases than BMI.

What kind of diseases, Doc?

Mainly obesity related ones such as high blood pressure, stroke and heart disease.

Ranges for a healthy body fat percentage?

The ideal body fat percentage range is a controversial topic amongst health professionals. Different authorities have differing views on what percentage of body fat is healthy. There are two main body fat percentage charts. One comes from the American Council on Exercise (ACE) and takes into account athletes and average fat percentages. The cut-off point of the amount of healthy fat for men is 25% and 32% for women. Another ideal body fat percentage chart is based on research from the late 1970’s (Jackson and Pollard) and also takes age into account. It is normal to carry a higher percentage of body fat as we age. See tables below:-

In young adults I prefer thresholds of 25% for men and 33% body fat percentage for women.

How to measure body fat.

There are several different ways to measure your percentage of body fat which we will briefly outline below. The key for individual progress however, is to be consistent with what method you use and do it regularly. This way you can see if you have lost weight whether this is fat loss or lean muscle loss. Use Dr Halls fat loss percentage calculatortoo. Here are a few methods:-

Skin fold testing: This method is one of the most accurate and takes us back to the ‘ if you can pinch more than an inch’ slogan which meant bad news. Using this method you measure how much adipose tissue (or fat) you have at different sites of the body with skinfold calipers. The fat caliper measures in millimetres and you enter the measurements from different body sites and get a body-fat percentage.

Bioelectrical impedance: These are sort of body fat scales used for measuring body composition especially amount of body fat, such as ‘ozeri touch‘ scales. Bioelectrical impedance analysis works by sending a light electric current through the body and then calculating body fat in accordance with the level of resistance.

I’m not keen on that picture, Doc. Is that where the saying ‘if you can pinch more than inch …’ comes from?

Oh Moose. I can pinch more than an inch on my forehead!

…and a Few more Fat Measuring Methods

Hydrostatic weighing is one of the most accurate methods for measuring body fat percentage. This involves going into a tank of water and being weighed. Another test similar to hydrostatic weighing is the bod pod which uses air displacement and whole body densitometry to separate fat cells from lean mass.

Anthropometric: This is similar to the principles and formulas behind the body fat percentage calculators. You simply take your measurements with a tape measure (or fat caliper) and enter the statistics to get a percentage body fat measurement.

Dexa scan: State of the art scanner that looks at body composition. This scan also shows you where fat is distributed around the body which can be important for predictions of your risk of some diseases.

Could you not just look at somebody to see how much body fat they have.

I know that you shouldn’t make fun of fat people because they have enough on their plates!

Here are some Questions and Answers

How is body fat percentage calculated? Your body fat percentage is calculated by taking your age, height and weight, gender and waist measurement into account. There are many different forms on how to measure and calculate your body fat percentage. Your results will help you determine a healthy weight and realistic weight loss goals based on the information you provided.

What is the body fat percentage for abs? The body fat percentage for nice abs is somewhere between 15% and 10%. Crazy bodybuilder-type-abs is around 7% and 3%.

What is the body fat percentage for bikini competition? A bikini competitor is anywhere from 8-13% body fat.

What body fat percentage is considered overweight? For women between ages 20-40, the overweight body fat percentage is between 33-39% and anywhere above 39% is considered obese. Women who are ages 41-60, the overweight body percentage is 35-40% and anywhere over 40% is considered obese. Whereas for men it’s a little bit different. Men between ages 20-40 overweight body fat percentage is between 19 and 25%. Obese is anywhere above 25%. Men ages 41-60, overweight is 22-27% and obese is anywhere over 27% body fat.

What does body fat percentage look like? As men gain body fat, the fat typically starts to go into the stomach area. As it grows, it will begin to form all over the body, but still mainly in the stomach. Wheres females, they typically see fat appearing into their hips and thighs. But women do see noticeable amounts of fat in their stomachs as well at even low body fat percentages.